forced draft fan

Forced Draft Fans for Industrial Applications

Forced Draft Fans

Forced draft fans, also called pressure blowers or FD fans, focus the pressure and volume at the outlet of the fan to push air through a system, creating positive air pressure.

Applications calling for positive pressure include burners or combustion air, cooling, and air drying processes, fumes and gas elimination, tempered glass, and other conditioning processes. Accommodating higher process inlet temperatures, industrial applications use forced draft fans to push ambient air through burners to preheat air for boiler system efficiency.
Your forced draft fan environment and airflow will dictate fan selection and specifications. Scroll or hyperlink down to find Application Featured Products, Case Studies, and further application details as follows:

Primary Industries for Forced Draft Fans

Forced draft fan applications are found across industries. However, because they are often used to feed combustion and high-temperature processes like dryers, burners, and boilers, you can be sure you’ll need forced draft fans in any or all of these industries:

  • Agricultural Processing
  • Automotive OEM
  • Building Materials
  • Chemical Processing
  • Food Processing
  • Glass Manufacturing
  • Metals & Mining
  • Oil & Gas
  • Paint & Surface Coatings
  • Pharmaceuticals
  • Power Plants
  • Printing, Packaging & Labeling
  • Pulp & Paper
  • Rubber & Plastics
  • Semiconductor & Electronics
  • Wastewater Treatment

Selection & Specification of Forced Draft Fans

Forced draft fans accommodate high process inlet temperatures, often working to push ambient air through burners to preheat air for boiler system efficiency. They can require less structural support and may offer a longer mechanical life than many induced draft fans because the cleaner ambient air is not as hard on the fan as induced draft applications.

Typical Types of Forced Draft Fans

Fan Arrangements

Fan Arrangements indicate how the motors mount to and drive the fans. Forced draft fans typically call for direct-drive, Arrangement 4 fans with variable frequency drives. Larger systems may require direct-coupled configurations while some users prefer belt-drive for speed flexibility. These are the arrangement options:

Arrangement 1 – Belt Drive with an overhung impeller. The fan and motor mount separately to a unitary base.

Arrangement 4 – Direct Drive with an overhung impeller. A low-cost arrangement, the fan wheel mounts directly on the motor shaft.

Arrangement 8: Direct Drive with an overhung impeller. The fan shaft is directly coupled to the motor shaft with a flexible coupling

Accessories & Design

“Pushing” ambient air involves less wear-and-tear on the fan than dirty and hot airstreams. The location of forced draft fans frequently allows for accessibility of upper bearings and the fan blades for maintenance and protects the fan and v-belt assembly from the hot-air stream. It also requires less structural support and can offer a longer mechanical life than many induced draft fans.

While ambient air may not be as hard on the fan compared to more extreme conditions, fan/system imbalance and excessive vibration can still be a problem. It’s critical that fan vibration levels are monitored and addressed if they exceed recommended levels.

Here are just some of the accessories and features you may see In forced draft fan applications:

Talk with Our Application Engineers

If you feel overwhelmed by all this information, don’t despair! We have a team of application engineers who are happy to talk with you and select the best fan for your application. You can call 715-365-3267, email, or send us your information, and one of our engineers will connect with you.

Related Content

Here are related posts and case studies that might be of interest as you think about your application.